1. Field of the Invention
The present invention relates to an ink jet recording ink.
2. Description of the Related Art
Ink-jet recording is a process in which an ink is ejected as small droplets from a minute nozzle to record characters or images on a surface of a recording medium. Techniques of ink-jet recording which have been put into practical use include: a method composed of converting electrical signals to mechanical signals with an electrostrictive element and intermittently ejecting an ink stored in a nozzle head to record characters or images on a surface of a recording medium; and a method composed of bubbling an ink stored in a nozzle head by rapidly heating that part of the ink which is located very close to the orifice and intermittently ejecting the ink based on the volume expansion caused by the bubbling to thereby record characters or images on a surface of a recording medium.
There have been required characteristics such as no blurring in printing to paper as the recording medium, good drying characteristic, uniform printability to the surfaces of various recording medium, and no mixture of adjacent colors in multicolor system printing such as color printing in such ink used for ink-jet recording.
In the conventional ink, particularly in a variety of kinds of ink using a pigment, the wettability of the ink to the surface of the paper is suppressed by mainly suppressing the permeability, and the securement of print quality is examined by confining ink drops near the surface of the paper. The ink has been put into practical use. However, in the ink which suppresses the wettability to the paper, the difference in blurring due to difference in paper types is large. Particularly, the blurring caused by the difference in wettability characteristics of the ink to each of the components occurs in recycled paper in which various components of paper are mixed. A problem exists in that it takes a long time to dry the printing in such ink and adjacent colors are mixed in multicolor system printing such as color printing. A problem also exists in that rubbing resistance is worsened since the pigment remains on the surface of the paper or the like in the ink using the pigment as a color material.
In order to solve the problems, the enhancement of the permeability of the paper to the paper has been attempted, and there have been examined the addition of diethylene glycol monobutyl ether (U.S. Pat. No. 5,156,675, specification), the addition of Surfynol 465 (manufactured by Nissin Chemical Industry Corporation) as an acetylene glycol system surfactant (U.S. Pat. No. 5,183,502, specification), or the addition of both the diethylene glycol monobutyl ether and the Surfynol 465(U.S. Pat. No. 5,196,056, specification). Or the use of ethers of diethylene glycol for ink has been examined (U.S. Pat. No. 2,083,372, specification).
It is generally difficult to enhance the permeability of an ink while securing the dispersion stability of a pigment in the ink using the pigment, and the range of selection of a penetrating agent becomes narrow. Some combinations of glycol ether and pigment include an example in which triethylene glycol monomethyl ether is used for the pigment (Japanese Published Unexamined Patent Application No. S56-147861), and an example using ethers of ethylene glycol, diethylene glycol or triethylene glycol for the pigment (Japanese Published Unexamined Patent Application No. H9-111165).
Examples of penetrating agents used for ink composition for thermal ink jet printing include 1,2-hexanediol, 1,2-octanediol, 2-methyl-2-propyl-1,3-propanediol (Japanese Published Unexamined Patent Application No. H9-3371).